RECENTLY, Stephens1 has suggested that the widespread silcretes of Central Australia can be explained by a sequence of three events: (1) mobilization of silica by lateritic weathering in the area of the present watershed of eastern and northern Queensland; (2) deposition of the silica after south-western transportation in streams and rivers for considerable distance (up to 900 miles) on a wide, gently sloping surface underlain by a large array of rocks; (3) erosive break-up of the silcrete sheet so formed due to rejuvenation, to leave caps on mesas and extensive stony pavements.